1. Field of the Invention
The present invention relates to workpiece supply and delivery systems situated upstream and downstream of the flow of a workpiece through one or more decorating stations of a decorating machine and, more particularly, to construction and operation of a workpiece transfer mechanism designed to operate about an angled axis for automatically changing a vertical to horizontal or a horizontal to vertical orientations of the workpieces with continuous motion or, if desired, intermittent motion.
2. Description of the Prior Art
U.S. Pat. Nos. 2,231,535; 2,261,255; 2,721,516; 3,146,705; 3,388,574; and 5,524,535 disclose intermittent motion type decorating machines using an indexing drive system to impart intermittent traveling motion to an endless conveyor chain provided with workpiece carriers used to supply workpieces such as a bottle made of glass or plastic. A chain conveyor disclosed in U.S. Pat. No. 3,388,574 is provided with workpiece carriers arranged in a side-by-side relation and used for supporting each bottle in a horizontal orientation while intermittently moved along a path of travel through a decorating apparatus. The bottle is supported at its opposite ends by clamping chucks one of which is driven by a crank arm on a journal extending from a bearing support and the other clamping chuck is moveable to releasably engage and rotatably support the bottle about a horizontal axis extending along the extended length of the bottle. The bottle is rotated by a drive member brought into a driving relation with the crank arm on the protruding journal from the bearing support. The clamping chucks are operatively supported on a base which is secured to chain-links forming the endless conveyor chain extending along the path of travel of bottles through the decorating machine.
In intermittent motion decorating machines, a bottle is moved by the endless chain conveyor through a predetermined distance, stopped, moved again through a predetermined distance, stopped and again moved until each bottle advances by the sequence of motions completely through all of the decorating stations of the decorating machine. A decorating station will be provided at one or more places where the bottle comes to a stop. The decorating cycle is essentially made up of two equal parts. One half of the decorating cycle is used for the decoration and the remaining half of the cycle is used for the indexing movement of the bottle through the decorating machine. There was no overlap between the decorating and indexing cycles.
At each decorating station while the bottle is stopped from traveling motion, a decorating screen is displaced into line contact by an associated squeegee with the surface of the bottle while the bottle is rotated about the longitudinal axis thereof. During the first part of the decorating cycle, the screen is moved synchronous with the peripheral speed of the rotating bottle to avoid smearing during decoration at the line contact established by a squeegee with the bottle. The squeegee remains stationary during the decorating process. When the screen moves to the end of its travel, the bottle has rotated 360° whereupon the screen drive mechanism maintains the screen stationary for the remaining part of the decorating cycle while the bottle is moved from the decorating station and an undecorated bottle is positioned at the decorating station.
Thermosetting ink was usually the printing medium in decorating machines, particularly when multiple color decoration was desired. Ink of only one color is applied at each decorating station and to decorate with multiple colors requires a multiple of corresponding decoration stations. When the different colors interleave in a given area of the bottle, because the same area is contacted with a screen for each color it is necessary that the applied ink/color is a solid and will not smear when additional ink/color is applied. Although the thermosetting ink is solidified after each printing operation, it is necessary to cure the ink by feeding the bottles through a furnace after discharging from the decorating machine. In co-pending patent application Ser. No. 09/079,753 filed May 15, 1998 there are disclosed a decorating method and apparatus to allow curing of ink decoration applied at one decorating station before additional decoration is applied. The dwell period of the intermittent advancing motion by the conveyor chain is used to apply decoration and to cure the applied decoration all at different spaced apart sites along the course of travel by the bottles in the decorating machine. All the decoration on a bottle delivered from the decoration machine can be cured so that the bottles can be loaded directly into a shipping container.
As disclosed in U.S. Pat. No. 5,524,535 the machine cycle in an intermittent motion decorating machine is altered to attain an increase to the workpiece decoration rate. The altered machine cycle provides that the portion of the cycle for conveyor indexing has a reduced duration in order to provide an increased part of the machine cycle for decorating. The conventional chain conveyor required an indexer drive to transmit the torque required to rapidly accelerate and decelerate a chain conveyor laden with carriers and including the compliment of bottles or workpieces processed in a decorating machine. A deviation to the use of a chain conveyor for workpieces in an intermittent decorating machine is disclosed in co-pending application Ser. No. 09/209,839, filed Oct. 8, 1998 and notably includes the use of elongated barrel cams and transfer disks arranged to provide a continuous traveling motion to workpiece carriers which is interrupted only at each decorating station and, when provided, at each curing station.
An alterative to an intermittent motion decorating machine is a continuous type motion decorating machine as disclosed, for example, in U.S. Pat. No. 3,251,298 to decorate a bottle during continuous, uninterrupted, linear travel on a conveyor along one or more spaced apart decorating stations. It is necessary to match the speed of the linear advancement of a squeegee at a decorating station with the linear speed of advancement of the bottle by the conveyor and match the speed of the peripheral speed of the bottle with the linear speed of a decorating screen. The occurrences of speed matching are required at each decorating station in the machine. The continuous motion of the conveyor eliminated the need for an indexer box to provide the intermittent motion by the conveyor in an intermittent motion decorating machine.
In U.S. Pat. No. 3,407,915 a main conveyor is constructed to reorientate workpieces from the generally vertical position to a generally horizontal position for registration and decoration and then back to a generally vertical position for discharge from the main conveyor. Unlike conventional conveyors for decorating machines, the conveyor has two functions, that is, its normal function of conveying the workpieces through the decorating machine and the additional function of reorienting the workpiece from a vertical position to a horizontal position and then back to a vertical position. The combination of the two functions sought to eliminate the need for additional equipment to reorientate the supply of bottles to and from the conveyor of the decorating machine.
U.S. Pat. No. 3,648,821 discloses a workpiece transferring apparatus to transfer workpieces individually from a supply conveyor to a decorator conveyor where decoration is applied while the workpieces are horizontally oriented in an intermittent type decorating machine and thence from a decorator conveyor to a delivery conveyor in which the transfer operations produce horizontal to vertical reorientations of the workpieces. The change to the workpiece orientation also occurs between a conveyor supplying bottles in a vertical orientation and the conveyor supplying the bottled in a horizontal orientation to a decorating machine. Each workpiece is repositioned by rotary type movements about two perpendicular and intersecting axes, one of which is the rotational axis of a rotary support shaft extending parallel with the rotational axes of the drive sprockets for the chain conveyor. The mass of material comprising the workpiece and support structure undergoing the rotary type movements limits the operating speed. Workpiece handling equipment disclosed in U.S. Pat. No. 5,524,535 enables an increase to the workpiece handling rate by a design of structural parts eliminating pivot arms positioned by a spring to reduce an adverse effect of inertia. Captive restraints hold each workpiece during transfer from a feed conveyor to the conveyor of the decorating machine and from the conveyor of the decorating machine to the delivery conveyor.
It is an object of the present invention to provide a workpiece transfer for suppling and unloading workpieces in a decorator machine by gripping and releasing each workpiece during the transferring operations by movement into and out of receiving and hand-off sites with great precision.
It is another object of the present invention to provide a workpiece transfer embodying a construction of parts to grip a workpiece while in a freestanding condition on a moving conveyor, reorientate and transfer the workpiece to a workpiece carrier while moving or at dwell period of operation of the conveyor system and then take the workpiece from the carrier while moving or at dwell period of operation by the conveyor system, reorientate the workpiece to again regain a freestanding condition and released for advancing movement by a moving conveyor.
It is another object of the present invention to provide an improved transfer for transferring workpieces for a decorator conveyor of a decorating machine to and/or from transport conveyors used to supply and/or deliver workpieces for the decorating machine.
It is a further object of the present invention to provide a workpiece transfer for moving workpieces by either an intermittent motion or continuous motion.
It is another object of the present invention to provide a workpiece transfer for moving workpieces to and/or from an intermittent chain conveyor system driven by an indexer box or, if desired, a continuous motion conveyor system using cams and workpiece carrier disks.
It is an object of the present invention to provide a workpiece transfer for supplying workpieces to a decorating machine particularly bottles at a greater throughput rate than heretofore attainable.
It is a further object of the present invention to provide an apparatus to transfer workpieces for either or both of the supply and unloading of workpieces from a decorating machine wherein the transfer is constructed for high speed motions between a supply conveyor where the workpieces are vertically oriented and a decorator conveyor where the workpieces are horizontally oriented for decoration as well as at the delivery end of the decorating conveyor where the workpieces again undergo high speed motions from the horizontal orientation to the vertical orientation on a discharge conveyor.